Track Width & Clearance Calcuation

[anish]

Hi,
For setting the design rules in Altium,
1.How to calculate the minimum & maximum trace Gap on each layer when the preferred trace width is provided by the PCB manufacturer?
2.How to calculate the trace width & Gap on the layers L2 & L11 (consider a 12 Layer PCB, L1-3-Signal,L4(GND),L5-L8(PWR),L9(GND),L10-L12 Signals) when the PCB manufacturer is not provided impedance calculation for the layers L2 & L11? Normally PCB manufacturers used to give the impedance calculated values only for routing layers, but here L2 & L11 is used for fanout requirement.
Thanks,
Anish

[robertferanec]

Hi anish,

1) you need to check with your PCB manufacturer, what is the minimum track and minimum gap what they can manufacture. For critical signals, you may want to increase gap, so signals do not influence each other. I recommend you to find more information about crosstalk topic. To be more specific, normally I do not use gap smaller than 0.1mm (4mil). Maybe have a look at this my post - especially Rule 6: Be aware of tracks running in parallel: High Speed PCB Design Rules (Lesson 4 of Advanced PCB Layout). Here you can also see example of table and recommended spacing based on H, where H is dielectricum height between signal layer and reference plane:



2) Please, what stackup are you referring to? If you are referring to the iMX6Rex stackup, L2 and L11 are grounds:

In case you would like to calculate track with by yourself, you can use an impedance calculator. I recommend you to have a look at Saturn PCB Toolkit - it's a free software and there are number of useful calculators in one place.

[anish]

Thank you..